The genetic is unstable, the Ruderalis traits (the auto flowering traits) aren’t locked down correctly.
It requires years of studies in the Mendelian laws of inheritance and a grade in genetic to correctly lock down traits on a first attempt in a genetic mapping... and such kind of people don’t work in a Cannabis breeding operation 😊
Here is a great video on YouTube to give you a hint on the fundamentals 😉:
https://youtu.be/9dHBTckFvME